双季稻每公顷年产18吨稻谷的施氮技术研究

The Study on Nitrogen Fertilizer Practice in Double-crop Rice with the Yield 18t/hm 2.a

在上等田和中上等田及中迟熟高产良种条件下，通过水稻生长前、中、后期氮素不同施用量和施用方法比较试验，改进水稻施氮技术。结果表明，一季总氮量１７２．５ｋｇ／ｈｍ２，可满足目标产量要求；水稻生长的前、中、后期施氮比例以６∶３∶１产量较高，并能达目标产量；前期分蘖肥以插秧后５～６ｄ适当重施氮肥，插秧后１０～１２ｄ轻施氮肥有利于控制无效分蘖和创造条件施穗肥；中期穗肥分２次施比１次施更有利于培育高产群体和提高穗粒数；后期适当施氮有显著增产效果。

The nitrogen fertilizer practice in double crop rice has been improved by our experiments including different quantities and different methods at the earlier, middle and later stages of the growth of rice. The result shows that the total nitrogen amount of 172.5kg/hm 2 can meet the requirement of the target yield of single-crop rice, and that higher output can be achieved with nitrogen applied at the earlier, middle and later stages respectively in a ratio of 6∶3∶1. It is also shown that the more nitrogen fertilizer practice for tillering at 5～6 days and less at 10～12 days after transplanting would advantageously control invalid tillers and could improve condition for fertilizer at spike stage. Dressing for earing, twice instead of once at the middle stage, much more advantage high-yield population and improve the grains/ear. Then, at the later stge, a higher production can be obtained significantly by the practice of approriate amount of nitrogen.